An oxidation catalyst for promoting combustion of PM is proposed. For example, in Japanese Patent Unexamined Publication No. 2007-54713, a diesel particulate filter is proposed, in which a decrease of a PM combustion temperature is attempted. This diesel particulate filter is a filter in which a catalyst that supports a platinum group such as Pt and Rh on an oxygen supply oxide including at least one of a zirconium-based multiple oxide and a cerium-based multiple oxide is coated on a ceramic-made honeycomb having alternately sealed channels.